When his friends throw him a wild bachelor party, he just wants to keep his conscience clean, but the next morning he he wakes up in bed with a beautiful girl. Guilt leads him to try to cover it up in the week before the wedding, high jinks ensue.
Through a series of misunderstandings, Alvin, Simon and Theodore come to believe that Dave is going to propose to his new girlfriend in Miami… and dump them. And there are only three days left for our lovely chipmunks to saving themselves not only from losing Dave but possibly from gaining a terrible stepbrother.
